Cisco Tips & Tricks

I was all geared up for my CCIE R&S lab in san jose.  I was a bit nervous as most of my lab practice came from job experience, plus some online workbook scenarios. Not to mention that I relied more or less on a non-conventional style of study. Dynamips was definitely a great help especially if you are running your dynamips on UBuntu Linux ( I love it).

I arrived in San Jose 2 days before my lab, and tried to manage my stress and jet lag. I promised myself that I would not look back in to my notes, but guess what i was so stressed that I started looking back in to my Qos,multicast and IP securtiy notes. I tried to have a good night sleep before the exam, but I was not able to sleep. I was getting cisco dreams all night.

I woke up at 6:30 in the morning and got ready for the exam, I had a yogurt for my breakfast as it was my wife’s suggestion. Arrived at site, checked in and the front desk guy asked for my ID, then he checked  me in with other candidates waiting in the lobby. I could see some going through notes and other just confused and lost. Proctor arrived at 8:15 and he acquainted us with rules and regulations.

by the lunch hour I was pretty confident as i thought I was doing well but right after the lunch I had some doubts, I skipped a few questions and moved on to the next. I finished rest of the tasks and the time was already 4:30. 30 minutes to go and i had still few tasks left which i had skipped earlier. I went back to the tasks and tried to finish all of them. By the time I finished all the tasks , my time was up.

I came out still confident and with a great hope that I would clear the lab. I was awake again whole night as the proctor told me that I would get a result the next morning. I checked my mail almost three times in the night but nothing fruitful came out of it. In the morning at almost 7:15 AM, I checked my mail again and I could see a mail from cisco. I logged in to Cisco with my CCO id, my heart was beating fast. To my surprise, I could see FAIL next to my score. What went wrong , I asked myself. My technology score was black and white enough to show me where I messed up.

For my secont attempt, I’ve signed up for Narbik’s bootcamp in June, and am planning to retry my lab within a few weeks of completing the bootcamp.

To view a IOS line parser

Show parser dump

Its an excellent command to see the selected functionality of the command. we can use it just like a Grep in Unix.

 For example:

R1#sh parser dump interface | include queue
15 tx-queue-limit Number
15 dialer hold-queue <0-100> timeout <1-2147483>
15 dialer hold-queue <0-100>
15 dialer hold-queue
15 funi rate-queue Number Number
15 funi rate-queue tolerance svc pvc 0 strict
15 funi rate-queue tolerance svc pvc 0
15 funi rate-queue tolerance svc pvc <5-99> strict
15 funi rate-queue tolerance svc pvc <5-99>
15 funi rate-queue tolerance svc 0 strict
15 funi rate-queue tolerance svc 0
15 funi rate-queue tolerance svc <5-99> strict
15 funi rate-queue tolerance svc <5-99>
15 funi rate-queue Number Number
15 funi rate-queue tolerance svc pvc 0 strict
15 funi rate-queue tolerance svc pvc 0
15 funi rate-queue tolerance svc pvc <5-99> strict
15 funi rate-queue tolerance svc pvc <5-99>
15 funi rate-queue tolerance svc 0 strict
15 funi rate-queue tolerance svc 0
15 funi rate-queue tolerance svc <5-99> strict
15 funi rate-queue tolerance svc <5-99>
15 funi rate-queue Number Number

or more extensively

Willow#show parser dump interface extend  | in queue.*(Enable|Configure)
tx-queue-limit : Configure card level transmit queue limit
srr-queue : Configure shaped round-robin transmit queues
srr-queue : Configure shaped round-robin transmit queues
srr-queue : Configure shaped round-robin transmit queues
fair-queue : Enable Fair Queuing on an Interface
fair-queue : Enable Fair Queuing on an Interface
fair-queue : Enable Fair Queuing on an Interface
fair-queue : Enable Fair Queuing on an Interface
fair-queue : Enable Fair Queuing on an Interface
tx-queue-limit : Configure card level transmit queue limit
srr-queue : Configure shaped round-robin transmit queues
srr-queue : Configure shaped round-robin transmit queues
srr-queue : Configure shaped round-robin transmit queues
fair-queue : Enable Fair Queuing on an Interface
fair-queue : Enable Fair Queuing on an Interface
fair-queue : Enable Fair Queuing on an Interface
fair-queue : Enable Fair Queuing on an Interface
fair-queue : Enable Fair Queuing on an Interface 

it can be pretty handy, if used intelligently. 

I came across a great resource, Cisco-centric Open Source Community (COSI). COSI is an Internet-based community that develops free Cisco tools and makes them available for download from its Web site. There are almost 50 utilities available for download. The scripts and utilities all include documentation, and the community has developed all of these tools to work with Cisco IOS routers, switches, firewalls, or CiscoWorks management software.

COSI’s Web site also offers other advantages. Clicking the link to download a script takes you to a community download page, which also features discussion forums for questions and support of these tools. It’s important to remember that Cisco’s Technical Assistance Center (TAC) doesn’t support these tools, so you must count on your own skills and the help of others in the community.

A tradeoff: These tools are not ideal for new Cisco IOS users or anyone who doesn’t have some Linux experience. Many of these tools help automate more advanced Cisco admin tasks when administering a midsize to large Cisco network

After starting a new assignment, I was in the middle of decision process on whether I should go for CCIE (SP) or not and I received the following mail from Cisco.

Recognizing the Sr. Level Network Designer
Introducing Cisco Certified Design Expert (CCDE) Certification
Responding to strong customer demand to assess and recognize Sr. Level Network Architecture skills in the market, Cisco is introducing a new premiere knowledge based certification focused on Network Infrastructure Design. - The Cisco Certified Design Expert (CCDE). The CCDE is an expert-level certification with content emphasis on expertise in network architecture, which is the capstone for Cisco’s design curriculum. In addition, passing the CCDE certification demands competencies of an experienced, seasoned, networking professional with a proven ability to interface with customers at the executive-level to ensure that business requirements are incorporated into successful designs.
What is a CCDE?
The successful CCDE-certified individual must have a demonstrated an ability to analyze and develop solutions which address planning, design, integration, optimization, operations, security and on-going support focused at the infrastructure of large 1000+ node customer networks.
The CCDE certification recognizes those with expert-level knowledge and skills in Infrastructure Design. The CCDE program is parallel to the CCIE program in terms of the expertise required and certification exam difficulty. It emphasizes network design principles and architectural theory of the network infrastructure and recognizes designers with the knowledge to assess network business requirements and translate them into technical specifications for successful designs.
Why Cisco Created the CCDE Program
Cisco created the CCDE program to respond to market demand in recognizing existing senior-level Network Designers and Architects while simultaneously providing senior Operations Engineers and Support Engineers with a validated professional development path into an Architectural role.
Cisco has found that organizations employing strong Network Designers and Architects consistently develop networks that are easier to maintain and troubleshoot. Properly executed, a well-designed network infrastructure aligned with a network-centric corporate business strategy leads to greater levels of efficiency and effectiveness - as well as potential competitive advantages like increased up-time, easier troubleshooting, increased performance, and simpler enhancements.
What are the exam requirements to attain CCDE?
To attain a CCDE certification a candidate will be tasked with passing two exams; a Qualification Exam, and a Practical exam. Similar to the CCIE program, there are no prerequisites to taking the Qualification exam and it is a 2 hour multiple-choice exam available at any worldwide Pearson VUE testing center. The Qualification exam, (ADVDESIGN) 352-001, assesses fundamental knowledge of networking theories, principles, protocols and technology.
Visit the CCDE program site for more details regarding the Qualification Exam ( www.cisco.com/go/ccde)
The second exam, the practical exam, is still currently in development. It will be an eight-hour, practical scenario-based exam available in late 2008. Bookmark the CCDE programs page as more details are expected to follow as the development team progresses.
The qualification exam is now available at Pearson VUE testing facilities worldwide.
More questions? Access the latest information on CCDE at www.cisco.com/go/ccde.
Feedback regarding CCDE, contact ccde_feedback@cisco.com

In OSPF we have 2 types of external routes. E1 and E2

For example 

R1#show ip route
Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

Route redistribution is the process of taking routes learned via one routing protocol and injecting those routes into another routing domain. (Static and connected routes can also be redistributed.) When a router running OSPF takes routes learned by another routing protocol and makes them available to the other OSPF-enabled routers it’s communicating with, that router becomes an Autonomous System Border Router (ASBR). Let’s say R1 is running both OSPF and RIP. R4 is in the same OSPF domain as R1, and we want R4 to learn the routes that R1 is learning via RIP. This means we have to perform route redistribution on the ASBR. The routes that are being redistributed from RIP into OSPF will appear as E2 routes on R4:R4#show ip route ospfO E2 5.1.1.1 [110/20] via 172.34.34.3, 00:33:21, Ethernet06.0.0.0/32 is subnetted, 1 subnets

.
R1(config)#router ospf 1
R1(config-router)#redistribute rip subnets metric-type 1 Now on R4, the routes appear as E1 routes and have a larger metric, since the entire path cost is now reflected in the routing table.O E1 5.1.1.1 [110/94] via 172.34.34.3, 00:33:21, Ethernet06.0.0.0/32 is subnetted, 1 subnets

One of my team member was asking me the question on routing decision. I thought of putting up here ..Any routing decision is based on the following rules.

1) Longest prefix length :- If we have two different routes in a routing table  for a same network, the longest prefix match is selected. lets say we have both 172.16.0.0/16 & 172.16.16.0/24 in the routing table.  In this case 172.16.16.0/24 will be selected.

2) AD ( Administrative distance) :- If longest prefix match cannot be considered for example if we have two routes with same prefix length then Route with lowest AD will be considered. Incase we have a same route learnt from IGRP and OSPF, IGRP route will be considered as it has alower AD(100) then OSPF (110).

3)Meteric:- If routes have same prefix length and same AD then a route with a better meteric is considered. In OSPF, cost~bandwidth is a meteric where as hop count is meteric for RIP.

4) Load sharing:- In case all the above three conditions match then  data  will be load balanced between the routes.

Normally with Router>Show ? , you will not see all available show commands at user level but there is a way to see Full help of Show commands at user level. You would need to enable following command

Router> terminal full-help

Enabling full help, you will witness that there are lot more commands available at User EXEC level.

The system administrator can also configure the system to always display full help for connections made to a particular line using the full-help line configuration command

redistribute static subnets command is used to redistribute static routes in OSPF, However static default route (ip route 0.0.0.0 0.0.0.0…) is not injected in to OSPF topology database. IF you want to redistribute static route in OSPF, following command should be used with in the router ospf configuration.

default-information originate always

Incase you issue above command without static route being configured, router will inject type 5 LSA for the default route in OSPF topology database.

Ping and trace are common utilities used by any Network Engineer to troubleshoot Network reachability problems. I have often seen that most of the times we are not interested in domain lookups while issuing tracert command.  Tracert -d is the best option I use to say ” Do not resolve addresses to hostnames”